Net Income Per Share Net Income Per Share (Computation Of Basic Earnings And Diluted Earnings Per Share) (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	3 Months Ended
	Jun. 30, 2015	Jun. 30, 2014
Antidilutive Securities Excluded from Computation of Net Income Per Share
Net income	$ 442	$ 335
Weighted Average Number of Shares Outstanding, Basic	311	313
Dilutive potential common shares related to stock award plans and from assumed exercise of stock options	8	8
Weighted Average Number of Shares Outstanding, Diluted	335	322
Basic	$ 1.42	$ 1.07
Diluted	$ 1.32	$ 1.04
Convertible Debt
Antidilutive Securities Excluded from Computation of Net Income Per Share
Incremental Common Shares Attributable to Dilutive Effect of Call Options and Warrants	10	1
Warrants
Antidilutive Securities Excluded from Computation of Net Income Per Share
Incremental Common Shares Attributable to Dilutive Effect of Call Options and Warrants	6	0